Functional Materials for Energy Storage: Fabrication of Shape Stabilized Polymeric Phase Change Composites and the Determination of Their Thermophysical Properties for Use in Energy Conservation Applications

Several polymeric thermal energy storage composites of high density polyethylene and polypropylene with two commercial paraffin waxes (PCM) P27 and P31 were prepared. The compounds were further reinforced with carbon fibers and carbon nanotubes to improve their thermal conductivity and heat transfer efficiency. The impact penetration behavior, service temperature and solvent resistance of the composites were improved by the addition of SEBS. DSC, optical microscopy, SEM, impact penetration and time–temperature history studies of the materials were done to determine the structure and thermal properties of these composites. The paraffins provide energy storage effect by solid–liquid phase change. The polymers encapsulate the paraffins so that the fluid motion of the PCMs is reduced during an application. The composites prepared were used for the construction of a small prototype swimming pool (laboratory scale). The time–temperature history of the composites, water in the container with and without energy storage materials and the environment was recorded. It was found that the composites significantly prolonged the cooling down time for water in the PCM pool. The difference between the cooling down temperature of water in a container with and without PCM composite was almost 4 hours. Moreover a computer program in C++ was written to solve the heat flow equations for the calculation of theoretical temperature–time curves.